RU2360845C2 - Method for protection against effect of wind disturbances at air intakes with ventral location on airplane - Google Patents

Abstract

FIELD: transportation.

SUBSTANCE: ground service facility is installed as obstacle against effect of wind disturbances at eddy generation under air intakes for reduction of eddy generation intensity in case of quartering headwind and posterolateral wind. Application of suggested plant makes it possible to reduce wind effect that increases intensity of eddy generation under air intakes and as a result to reduce probability of preterm dismantling of airplane engines because of foreign objects ingress.

EFFECT: reduced effect of wind disturbances at intensity of eddy generation under two air intakes of airplane with ventral location due to rational installation of technical service facilities.

5 dwg

Description

The invention relates to the field of aviation, in particular to ground-based means of protecting aviation gas turbine engines from the ingress of foreign objects (stones, ice, dirt, etc.).

There is a method for protecting engines from the ingress of foreign objects, isolating a small portion of the surface of the airfield under the cut of the air intake (11.9966.0.000.000 Unified maintenance schedule No. 10). It is carried out on a small platform of a special form on wheels, with a perimeter guard grill located under the air intake.

The disadvantage of this method of protection is the limited use of the device only on the gas platform for one aircraft.

The proposed method of placement of ground handling facilities (SSS) during the flight of aircraft with a ventral arrangement of air intakes will significantly reduce the intensity of vortex formation in the opposite-lateral or posterolateral direction of the wind.

The technical problem to be solved is the reduction of the influence of wind disturbances on the vortex formation intensity under two air intakes with a fuselage arrangement due to the rational placement of maintenance facilities.

у поверхности аэродрома, которая зависит от ряда конструктивных и эксплуатационных факторов.The parameter reflecting the intensity of the vortex cords can be the value of the maximum horizontal velocity,

at the surface of the airfield, which depends on a number of design and operational factors.

,

,

where H is the height of the air intake;

G _in - air flow through the air intake;

V _in - speed of the oncoming flow;

β is the angle of the oncoming flow;

- эквивалентный диаметр входа в воздухозаборный канал (S - площадь входного сечения воздухозаборника).

- equivalent diameter of the inlet to the air intake channel (S is the inlet cross-sectional area of the air intake).

Studies of the dependence of the vortex formation intensity under the air intakes on wind conditions and the placement of maintenance facilities were carried out on a special installation. The wind was modeled using a wind blower, which is a duct with a fan at the inlet and a rectifier grill at the outlet. Wind speed was regulated by a radial slotted inlet flap. The transition from a real aircraft to its model required the observance of gas-dynamic similarity: Re> Re _cr , the equivalent diameter of the air intake D _equ . The model of the Su-27 aircraft and ground handling facilities are made at a scale of 1:24. The flow velocity in both air intakes is the same with = 100 m / s.

Studies of the influence of wind direction and speed on the intensity of vortex formation under the fuselage air intakes were carried out using a TTM-2 microprocessor-based hot-wire anemometer with kinematic, dynamic, and geometric similarities. For the zero direction of the wind, the opposite direction is taken. Measurements V _G. were performed along the midline of each air intake on the surface of the aerodrome at a distance of 3 D _equiv from the air inlet section with an interval of 0.3 D _equiv . The results showed that:

1. The vortex begins to be deflated by the oncoming flow, V _at > 6 m / s.

2. At β = 30 ° ÷ 60 °, one vortex is formed under the left air intake on the leeward side.

3. A significant increase in the intensity of vortex formation is observed when the direction β = 30 ° ÷ 60 °, β = 120 ° ÷ 150 ° (see Figure 1, 2).

4. The maximum intensity of vortex formation is observed when the wind speed V _in = 3-6 m / s, the direction β = 30 ° ÷ 60 ° and the wind speed V _in = 5-8 m / s, the direction β = 120 ° ÷ 150 °.

от скорости и направления ветра, соответственно под левым и правым воздухозаборниками, где:Figure 1, 2 presents the dependence

from the speed and direction of the wind, respectively, under the left and right air intakes, where:

при безветрии;0 - change

with no wind;

при V_в=1-2 м/с;1 - change

at V _in = 1-2 m / s;

при V_в=2-3 м/с;2 - change

at V _in = 2-3 m / s;

при V_в=3-4 м/с;3 - change

at V _in = 3-4 m / s;

при V_в=4-5 м/с;4 - change

at V _in = 4-5 m / s;

при V_в=3-6 м/с.5 - change

at V _in = 3-6 m / s.

под левым и правым воздухозаборниками за счет рационального размещения средства наземного обслуживания при производстве полетов, где А - изменение

под правым воздухозаборником и А' - изменение

под левым воздухозаборником.Figure 3 change

under the left and right air intakes due to the rational placement of ground handling facilities during operations, where A is the change

under the right air intake and A '- change

under the left air intake.

Figure 4 shows the layout of ground handling facilities (SSS) during flight operations for aircraft with a ventral arrangement of air intakes where:

1 - location of CHO β = 45 °;

2 - location of CHO β = 135 °;

3 - location of CHO β = -135 °;

4 - location of CHO β = -45 °.

Figure 5 shows a diagram of taxiing aircraft during flight operations.

The method of locating ground handling facilities when flying for aircraft with a fuselage arrangement of air intakes consists in the specific location of the ground handling facility (an aerodrome mobile unit based on the Ural car) used in preparing the aircraft and starting engines on all types of aircraft.

The ground handling facility is installed as an obstacle to the effects of wind to reduce the vortex formation intensity under the air intakes under the following conditions:

1. velocity V _in = 3-6 m / s, direction β = ± 30 ° ÷ 60 °.

2. velocity V _in = 3-8 m / s, direction β = ± 120 ° ÷ 150 °,

where V _in is the speed of the oncoming flow, β is the angle of the oncoming flow.

The used ground handling facility is located according to the proposed layout of the ground handling facility during operations (see Figure 4).

The method of placement of ground handling facilities in flight for aircraft with a fuselage arrangement of air intakes is as follows. In the event of wind effects on the gas pad, the horizontal component of the wind velocity is added at the horizontal speed of the air masses pulled into the air intake. As a result of the addition of velocities, the intensity of the vortex flows increases. The ground handling facility is located in the path of the wind flow (counter-lateral or posterolateral). At the recommended location of the ground handling facility, the incoming wind flow, colliding with the facility, changes its direction and brakes. Consequently, the intensity of vortex formation is significantly reduced.

под левым и правым воздухозаборниками с применением предлагаемого способа и без него (направление ветра β=30°÷60°, скорость ветра V_в=3-5 м/с, размещение средства наземного обслуживания β=45°). Применение предлагаемого способа при встречном направлении ветра запрещено согласно схеме размещения зон повышенной опасности от работающих двигателей.Figure 3 presents the change

under the left and right air intakes using the proposed method and without it (wind direction β = 30 ° ÷ 60 °, wind speed V _in = 3-5 m / s, placement of ground handling equipment β = 45 °). The application of the proposed method in the opposite direction of the wind is prohibited according to the layout of areas of increased danger from running engines.

The application of the proposed method will reduce the influence of wind, which increases the intensity of vortex formation under the air intakes, and as a result, reduce the likelihood of early removal of engines due to the ingress of foreign objects. In addition, the proposed method will reduce the impact of a jet stream and the throwing of foreign objects by a jet jet by a taxiing aircraft during flight operations (see Figure 5).

Claims (3)

A method of protecting against the influence of wind disturbances on air intakes with a fuselage arrangement on an airplane during flight, which consists in a specific arrangement of ground handling facilities or airfield mobile units, characterized in that ground handling facilities are installed as an obstacle in the direction of wind flow against the side-side or rear-side, where the incident wind flow, colliding with the tool, changes its direction and brakes, reducing the intensity of the vortex To the following conditions: 1. speed V _in = 3-6 m / s, direction β = ± 30 ° ÷ 60 °; 2. velocity V _in = 3-8 m / s, direction β = ± 120 ° ÷ 150 °,
where V _in is the speed of the oncoming flow, β is the angle of the oncoming flow.

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